Method of determining adaptive DPI curve

ABSTRACT

A method of determining an adaptive DPI curve includes the steps of: detecting, by a sensing element, an object on a touch surface and outputting a detected frame; calculating, by a processing unit, a contact range according to the detected frame; and determining a DPI curve according to the contact range.

RELATED APPLICATIONS

The present application is based on and claims priority to TaiwaneseApplication Number 103102427, filed Jan. 23, 2014, the disclosure ofwhich is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Field of the Disclosure

This disclosure generally relates to a touch control device and, moreparticularly, to a touch control device and a determining methodthereof, which determine a DPI curve according to contact areas ofdifferent objects.

2. Description of the Related Art

The conventional touch control device, such as a touch pad, generallyhas a touch surface and a processing unit. When a user moves his/herfinger on the touch surface, the processing unit calculates atwo-dimensional coordinate position of the finger corresponding to thetouch surface and generates a displacement signal. Then, the processingunit outputs the displacement signal with a DPI (dots per inch) value toa host and correspondingly controls a cursor movement of the host.

FIG. 1A is a schematic diagram of a DPI curve, wherein the x-axisindicates a moving velocity (unit: inch per sec) of an object (e.g. thefinger), and the y-axis indicates a cursor DPI corresponding to theobject. The DPI curve represents a relationship between a movingvelocity of a cursor and dots per inch. When a moving velocity of anobject is slower, e.g. for editing an image, the cursor DPI becomessmaller so that a cursor corresponding to the object is accurately movedwithin a small region. And when the moving velocity is faster, e.g. forplaying a computer game, the cursor DPI becomes larger so that theobject controls the cursor to move for a long distance without movingtoo far. Therefore, an input device using a DPI curve provides a betteruser experience.

However, fingers of different users (e.g. adults and children) or evendifferent fingers of the same user change a contact range with the touchsurface. Thus, within the region of the touch pad, especially for a minitouch pad, a movable distance for a big object is obviously smallercompared to a movable distance for a small object. For example,referring to FIG. 1B, when an index finger 93 with a smaller contactrange horizontally moves on a touch pad 91 from the left side to theright side thereof, a maximum travel distance X₉₃ is obtained. When athumb 95 with a larger contact range horizontally moves on the sametouch pad (shown as 91′ herein) from the left side to the right sidethereof, another maximum travel distance X₉₅ is obtained. Obviously,since the contact range of the index finger 93 is smaller than that ofthe thumb 95, the maximum travel distance X₉₃ is larger than the maximumtravel distance X₉₅. Accordingly, cursors C₉₃ and C₉₅ on display screens81 and 81′ corresponding to the touch pads 91 and 91′ respectively moveover distances X₉₃′ and X₉₅′, wherein X₉₃′>X₉₅′. Therefore, a shortertravel distance for a bigger object leads to the problem of a shortertravel distance for a cursor being moved.

SUMMARY

Accordingly, the present disclosure provides a touch control device anda determining method thereof that determine different DPI curves throughcalculating contact ranges of different objects.

The present disclosure provides a method of determining an adaptive DPIcurve and a touch control device using the same that determine differentDPI curves through calculating contact ranges of different objects.

The present disclosure further provides a method of determining anadaptive DPI curve and a touch control device using the same that havethe effect of allowing travel distances of the cursor corresponding todifferent objects to substantially be identical.

The present disclosure provides a touch control device with an adaptiveDPI curve. The touch control device includes a touch surface, a sensingelement and a processing unit. The touch surface is configured for anobject operating thereon. The sensing element is configured to detectand output a detected frame of the object in contact with the touchsurface. The processing unit is configured to calculate a contact rangeaccording to the detected frame and determine a DPI curve accordingly.

The present disclosure further provides a method of determining anadaptive DPI curve. The method includes the steps of: detecting, by asensing element, an object in contact with a touch surface andoutputting a detected frame; calculating, by a processing unit, acontact range according to the detected frame; and determining a DPIcurve according to the contact range.

The present disclosure further provides a method of determining anadaptive DPI curve. The method includes the steps of: detecting, by asensing element, a first object in contact with a touch surface at afirst time and outputting a first detected frame; calculating, by aprocessing unit, a first contact range according to the first detectedframe; detecting, by the sensing element, a second object in contactwith the touch surface at a second time and outputting a second detectedframe; calculating, by the processing unit, a second contact rangeaccording to the second detected frame; and determining a DPI curveaccording to a variation between the second contact range and the firstcontact range.

In one embodiment, a contact range is obtainable according to acomparison result between the detected variation of a plurality ofdetection units of a sensing element and a threshold.

In one embodiment, a processing unit calculates a sum of intensities ofeach column or each row of detection units in a detected frame to obtaina variation curve, and the contact range is calculated according to thevariation curve.

The touch control device according to the embodiment of the presentdisclosure calculates a contact range of an object on a touch surfaceand determines a DPI curve according to the contact range. In addition,the accuracy for determining a DPI curve is improved through calculatinga variation between contact ranges of the object according to detectedframes successively outputted from the sensing element.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, advantages, and novel features of the present disclosurewill become more apparent from the following detailed description whentaken in conjunction with the accompanying drawings.

FIG. 1A is a schematic diagram of a DPI curve.

FIG. 1B is a schematic diagram of different fingers operating on a touchpad and cursor movements corresponding thereto.

FIG. 2A is a schematic diagram of a touch control device with anadaptive DPI curve according to one embodiment of the presentdisclosure.

FIG. 2B is a schematic diagram of the touch control device of FIG. 2Aintegrated with a keyboard.

FIG. 3 is a flow chart of a method of determining an adaptive DPI curveaccording to a first embodiment of the present disclosure.

FIG. 4A is a perspective drawing of a sensing element of a touch controldevice according to one embodiment of the present disclosure.

FIG. 4B is a curve diagram of the capacitance variation of the touchcontrol device in FIG. 4A.

FIGS. 5A-5D are schematic diagrams of a plurality of DPI curves.

FIG. 6 is a flow chart of a method of determining an adaptive DPI curveaccording to a second embodiment of the present disclosure.

FIG. 7A is a perspective drawing of a sensing element of a touch controldevice according to one embodiment of the present disclosure.

FIG. 7B is a curve diagram of the capacitance variation of the touchcontrol device of FIG. 7A.

DETAILED DESCRIPTION OF THE EMBODIMENT

It should be noted that, wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

FIG. 2A is a schematic diagram of a touch control device 1 with anadaptive DPI curve according to one embodiment of the presentdisclosure. The touch control device 1 includes a touch surface 10, asensing element 12 and a processing unit 14. The sensing element 12 iselectrically connected to the processing unit 14. A user touches thetouch surface 10 with an object 2 (a finger shown herein), and theprocessing unit 14 calculates a position or a position variation of theobject 2 with respect to the touch surface 10 according to detectedframes F generated by the sensing element 12 successively detecting theobject 2. A cursor (not shown) on a display device correspondingly movesaccording to the position or the position variation. It is appreciatedthat a host is generally connected between the touch control device 1and the display device for transferring the position or the positionvariation to an electrical signal.

The touch control device 1 may be integrated with a keyboard K, as shownin FIG. 2B, wherein two integrated methods are exemplarily shown. Thekeyboard K has a plurality of keys (i.e. key caps). In one aspect, thetouch control device 1 is integrated with one key Kb of the plurality ofkeys; meanwhile, a press function of the key Kb is also reserved. Inanother aspect, the touch control device 1 is independently integratedon the keyboard K without being integrated with any key, for example, anupper region relative to arrow keys.

The touch control device 1 of the present disclosure is not limited tobe integrated with the keyboard K. In one embodiment, the touch controldevice 1 is integrable with other devices, for example a fingerprintrecognition module, to form a multi-function touch pad. In otherembodiments, the touch control device 1 is integrated with a navigationdevice (e.g. a presenter, a remote controller or a game pad), acellphone or a computer system.

Referring to FIG. 2A continuously, the touch surface 10 is configuredfor an object 2 operating thereon. Since the touch control device 1corresponds to a display device, the touch surface 10 and the displaydevice may have an identical shape, e.g. a rectangular shape, but notlimited thereto. The touch surface 10 is a surface of an appropriateobject.

The sensing element 12 is configured to detect and output a detectedframe F of the object 2 in contact with the touch surface 10. In thepresent embodiment, the sensing element 12 is disposed below the touchsurface 10, as shown in FIG. 2A, but not limited thereto. The relativeposition between the sensing element 12 and the touch surface 10 isdetermined according to the actual application.

In one embodiment, the sensing element 12 is a capacitive touch sensor,wherein the capacitive touch sensor has a plurality of detection units.When the object 2 contacts the touch surface 10, the detection unitsunder the object 2 and around the object 2 correspondingly generate thecapacitance variation, and then the sensing element 12 outputs adetected frame F. Similar to the capacitive touch sensor, when aresistive touch sensor or an optical touch sensor is used as the sensingelement 12, the sensing element 12 outputs detected frames F includingvoltage variations or photosensitive variations. For simplifying thedescription, the capacitive touch sensor is used as the sensing element12 in the embodiment of the present disclosure.

The principles and structures of the capacitive touch sensor, resistivetouch sensor and optical touch sensor mentioned above are well known,and thus details thereof are not described herein. It should bementioned that the material of the object 2 is not particularly limitedand is determined according to the type of the sensing element 12. Forexample, when the sensing element 12 is a capacitive touch sensor, theobject 2 is preferably a finger or a capacitive touch pen. When thesensing element 12 is an optical touch sensor, the object 2 preferablyhas light blocking characteristics.

The processing unit 14 is, for example, a digital signal processor (DSP)or other processing devices that are configured to process the detectedframe F so as to calculate a contact range R. Then, the processing unit14 determines a DPI curve or a DPI value according to the contact rangeR. The calculating and determining method thereof are described later.

It should be mentioned that a plurality of DPI curves are preferablystored in a memory unit (not shown) or in the processing unit 14 of thetouch control device 1 before shipment. Therefore, the processing unit14 determines one of the plurality of DPI curves according to differentobject areas so that the touch control device 1 has the characteristicof an adaptive DPI curve.

FIG. 3 is a flow chart of a method of determining an adaptive DPI curveaccording to a first embodiment of the present disclosure, whichincludes the following steps of: detecting, by a sensing element, anobject in contact with a touch surface and outputting a detected frame(step S₁₁); calculating, by a processing unit, a contact range accordingto the detected frame (step S₁₂); and determining a DPI curve accordingto the contact range (step S₁₃).

It should be mentioned that the sensing element 12 has a plurality ofdetection units. For example, FIG. 4A exemplarily shows that theplurality of detection units of the sensing element 12 are arranged in a5×5 detection-unit array, wherein each of the detection units, from leftto right and from up to down, is successively labeled as G₁, G₂ . . .G₂₅. It is appreciated that when the touch control device 1 does notdetect any object, each detection unit has a predetermined capacitance;and when the object 2 contacts the touch surface 10, the detection unitsinduced with the object 2 in the sensing element 12 respectivelygenerates a capacitance variation. For simplifying description, acapacitance variation is directly shown inside each detection unit inFIG. 4A. For example, the detection unit G₆ is shown with a capacitancevariation of 4; and the detection unit G₂₅ is shown with a capacitancevariation of 0. It should be mentioned that values shown in FIG. 4A areonly intended to illustrate, not to limit the present disclosure.

Referring to FIGS. 2A, 3, 4A, 4B and 5A together, details of the presentembodiment are described hereinafter.

Step S₁₁: Firstly, when the object 2 contacts the touch surface 10, thedetection units in the sensing element 12 induced with the object 2respectively generate a capacitance variation. It is appreciated thatthe detection unit closer to the object 2 has a larger capacitancevariation according to the induction capacitance principle; otherwise,the detection unit farther away from the object 2 has a smallercapacitance variation or even has no capacitance variation. The sensingelement 12 outputs a detected frame F containing the capacitancevariation information to the processing unit 14.

Step S₁₂: After receiving the detected frame F from the sensing element12, the processing unit 14 calculates a contact range R₁ according tothe detected frame F, wherein the contact range R₁ reflects a contactwidth, a contact length or a contact area of the object 2.

In a first aspect, the processing unit 14 compares each capacitancevariation with a threshold. For example, the threshold is set to be 10,and the capacitance variation of 5 of 25 detection units in the sensingelement 12 (i.e. detection units G₇, G₁₁-G₁₃ and G₁₇) is larger than 10.Therefore, the comparison result (i.e. 5) is configured to calculate thecontact range R₁. For example, the contact range R₁ may be 5, 25 or amultiple of 5.

In a second aspect, the processing unit 14 calculates a sum or anaverage value of the entire capacitance variations. For example, a sumof capacitance variations of all the detection units in the sensingelement 12 is 208. Therefore, the calculating result (i.e. 208) directlyindicates the contact range R₁ or is configured to calculate the contactrange R₁.

In addition, the processing unit 14 further obtains a variation curveaccording to a sum of intensities of each column or each row of thedetected frame F of the sensing element 12 and calculates the contactrange R₁ accordingly. For example, referring to FIG. 4B, it is acapacitance variation curve of the touch control device 1 in FIG. 4A,wherein the x-axis indicates the position of detection unit column; andthe y-axis indicates the sum of capacitance variations thereof. It isassumed that a threshold of the sum of capacitance variations is 100, apart of the capacitance variation curve of FIG. 4B larger than thethreshold forms a width W₁. Therefore, the processing unit 14 calculatesthe contact range R₁ accordingly. For example, the width W₁ isconfigured to indicate a contact width or a contact area of the contactrange R₁.

Step S₁₃: Finally, the processing unit 14 determines a DPI curveaccording to the contact range R₁. For example, referring to FIG. 5A, itis a schematic diagram of two DPI curves of the touch control device 1,wherein the DPI curves DPI₁ and DPI₂ are respectively associated with acontact range R₁. For example, the DPI curve DPI₁ is selected when thecontact range R₁ is smaller than 6, and the DPI curve DPI₂ is selectedwhen the contact range R₁ is equal to or larger than 6. When the contactrange R₁ is calculated as 5 through the above mentioned method of thefirst aspect, the processing unit 14 identifies that the contact rangeR₁ satisfies the condition of the DPI curve DPI₁ and determines to usethe DPI curve DPI₁. Similarly, it is assumed that the DPI curve DPI₁ isselected when the contact range R₁ is smaller than 200, and the DPIcurve DPI₂ is selected when the contact range R₁ is equal to or largerthan 200. When the contact range R₁ is calculated as 208 through theabove mentioned method of the second aspect, the processing unit 14identifies that the contact range R₁ satisfies the condition of the DPIcurve DPI₂ and determines to use the DPI curve DPI₂. In anotherembodiment, the DPI curve DPI₁ corresponds to a first contact-rangeinterval and the DPI curve DPI₂ corresponds to a second contact-rangeinterval. The contact range is compared with a contact-range intervalbut not simply compared with a contact threshold.

That is to say, the method for calculating the contact range and thecondition for determining the DPI curve of the processing unit 14 arepreviously stored in the touch control device 1 before shipment. Forexample, a plurality of DPI curves are previously stored in the touchcontrol device 1, and the processing unit 14 selects one of theplurality of DPI curves according to the calculated contact range inactual operation. Therefore, no matter how the size of the object 2operating on the touch control device 1 changes, the processing unit 14determines a most appropriate DPI curve according to the contact rangecorresponding to the object 2.

FIGS. 5A-5D are schematic diagrams of a plurality of DPI curves, whereinFIG. 5A and FIG. 5B respectively include two DPI curves; and FIG. 5C andFIG. 5D respectively include three DPI curves. The DPI curve is astraight line, an exponential curve or a monotonic increasing curve, butnot limited thereto. The number and type of the DPI curve previouslystored in the touch control device 1 is determined according to theactual application.

Generally speaking, when a user operates an object on the touch surface10, the touch control device 1 outputs the displacement information at ahigher cursor DPI with a faster moving velocity of the object. Forexample, referring to FIG. 5C, the DPI curves DPI₅ and DPI₆ indicatethat the faster the moving velocity is, the higher the cursor DPI is;and the DPI curve DPI₇ indicates the cursor DPI does not change with themoving velocity. Therefore, a variation tendency of the DPI curve isassociated with or independent from a moving velocity of the objectoperating on the touch surface 10. In one embodiment, it is assumed thatthe DPI curves DPI₅, DPI₆ and DPI₇ respective correspond to theoperation of a thumb, an index finger and a touch pen. When the thumb orthe index finger is used to operate on the touch surface 10, the touchcontrol device 1 outputs the displacement information respectively withthe DPI curve DPI₅ or DPI₆. It is appreciated that the contact range ofthe touch pen may be much smaller than the contact range of the thumb orthe index finger. Therefore, when the touch pen is used to operate onthe touch surface 10, the displacement information is outputted with afixed cursor DPI (i.e. DPI). More specifically, when the DPI curve isirrelevant to the moving velocity of the object, the DPI curve may be aDPI value.

FIG. 6 is a flow chart of a method of determining an adaptive DPI curveaccording to a second embodiment of the present disclosure, whichincludes the following steps of: detecting, by a sensing element, afirst object in contact with a touch surface at a first time andoutputting a first detected frame (step S₂₁); calculating, by aprocessing unit, a first contact range according to the first detectedframe (step S₂₂); determining an initial DPI curve according to thefirst contact range (step S₂₃); detecting, by the sensing element, asecond object in contact with the touch surface at a second time andoutputting a second detected frame (step S₂₄); calculating, by theprocessing unit, a second contact range according to the second detectedframe (step S₂₅); and determining a DPI curve according to a variationbetween the second contact range and the first contact range (step S₂₆).

Referring to FIGS. 2A, 4A, 4B, 6, 7A and 7B together, it is assumed thatthe status of FIG. 4A is the first time and the status of FIG. 7A is thesecond time, and then details of the present embodiment are describedhereinafter.

Step S₂₁: Firstly, a first object contacts the touch surface 10 at thefirst time, and a plurality of detection units in the sensing element 12correspondingly generate capacitance variations, as shown in FIG. 4A.Then, the sensing element 12 outputs a first detected frame to theprocessing unit 14 according to the capacitance variations.

Step S₂₂: After receiving the first detected frame from the sensingelement 12, the processing unit 14 calculates a first contact range(e.g. the contact range R₁) according to the first detected frame.

Step S₂₃: Similar to the first embodiment of the present disclosure, theprocessing unit 14 determines an initial DPI curve according to thefirst contact range. It should be mentioned that the step S₂₃ isconfigured to avoid that the touch control device 1 may not outputdisplacement information with an appropriate DPI curve when the firstobject is moving on the touch surface 10 before determining a DPI curvein the step S₂₆. It is appreciated that when the touch control device 1has a higher sampling rate, a time difference between the first time andthe second time may be ignored. That is to say, a DPI curve isdetermined (i.e. the step S₂₆ is accomplished) before the first objectbegins to move, and the step S₂₃ is ignorable. In another embodiment,the step S₂₃ may not be implemented and the touch control device 1operates with the initial DPI curve before the step S₂₁. The stepsS₂₄-S₂₆ are configured to determine whether the contact area of theobject is changed enough to change the DPI curve.

Step S₂₄: Then, the second object contacts the touch surface 10 at thesecond time, and a plurality of detection units in the sensing element12 correspondingly generate capacitance variations, as shown in FIG. 7A.And, a second detected frame is outputted to the processing unit 14accordingly. It is appreciated that the second object and the firstobject may be an identical object such as an index finger. But for thesensing element 12, objects detected at different times are identifiedas different objects even though the detected objects are actually anidentical object.

Step S₂₅: Similarly, the processing unit 14 calculates a second contactrange (e.g. the contact range R₂) according to the second detectedframe.

As mentioned above, the second contact range and the first contact rangeof the step S₂₂ are respectively obtainable according to a comparisonresult between the detected variation of a plurality of detection unitsand a threshold. Or, the processing unit 14 respectively calculates asum of intensities of each column (or each row) of the first detectedframe and the second detected frame so as to obtain variation curves;and the first contact range and the second contact range are thenrespectively calculated according to the variation curves. The method ofcalculating the first contact range and the second contact range isidentical with that of calculating the contact range R₁ according to thefirst embodiment of the present disclosure, and thus details thereof arenot described herein.

Step S₂₆: Finally, the processing unit 14 determines a DPI curveaccording to a variation between the second contact range and the firstcontact range, wherein the variation is a difference value between thesecond contact range and the first contact range, or a result (i.e.quotient) of dividing the second contact range by the first contactrange. For example, the variation is calculated by subtracting thecontact range R₁ of FIG. 4A from the contact range R₂ of FIG. 7A. Or,the variation is calculated by dividing the contact range R₂ by thecontact range R₁, but not limited thereto.

The difference between the determining method in the present embodimentand that in the first embodiment is that the touch control device 1 inthe first embodiment determines a DPI curve according to a touch areabetween the object 2 and the touch surface 10; and the touch controldevice 1 in the second embodiment determines a DPI curve according to avariation between contact areas of the object 2 in contact with thetouch surface 10.

In the above embodiments, a capacitive touch sensor is used to describethe operating method of the sensing element 12 so that the firstdetected frame and the second detected frame include capacitancevariations of a plurality of detection units in the sensing element 12.It is appreciated that when a resistive touch sensor is used as thesensing element 12, the detected frames include voltage variations of aplurality of detection units in the sensing element 12; and when anoptical touch sensor is used as the sensing element 12, the detectedframes include photosensitive variations of a plurality of detectionunits in the sensing element 12.

It should be mentioned that DPI (dots per inch) is used to indicate thecursor moving in the above embodiments, but not limited thereto. Thoseskilled in this art know CPI (count per inch) can also be used toindicate the cursor moving.

In one embodiment, the processing unit 14 only determines a DPIswitching signal, and an electronic device coupled with the touchcontrol device 1 selects a DPI value or a DPI curve according to the DPIswitching signal.

As mentioned above, the conventional touch control device cannotcorrespondingly change a DPI curve thereof corresponding to differentobjects. Therefore, the present disclosure provides a touch controldevice (FIG. 2A) and a method of determining the DPI curve (FIGS. 3 and6) by calculating contact ranges of different objects to determinedifferent DPI curves, and accordingly solves the problem of theinconsistency between different objects and corresponded differenttravel distances of the cursor.

Although the disclosure has been explained in relation to its preferredembodiment, it is not used to limit the disclosure. It is to beunderstood that many other possible modifications and variations can bemade by those skilled in the art without departing from the spirit andscope of the disclosure as hereinafter claimed.

What is claimed is:
 1. A method of determining an adaptive dots per inch(DPI) function, the method comprising: detecting, by a sensing element,a first object in contact with a touch surface at a first time, andoutputting first detected data; calculating, by a processing unit, afirst contact range corresponding to the first object on the touchsurface according to the first detected data; detecting, by the sensingelement, a second object in contact with the touch surface at a secondtime, and outputting second detected data; calculating, by theprocessing unit, a second contact range corresponding to the secondobject on the touch surface according to the second detected data; anddetermining a DPI function according to a variation between thecalculated second contact range of the second object and the calculatedfirst contact range of the first object on the touch surface.
 2. Themethod as claimed in claim 1, further comprising: determining an initialDPI function according to the first contact range.
 3. The method asclaimed in claim 1, wherein in the determining, the processing unitselects one of a plurality of DPI functions according to the variation.4. The method as claimed in claim 1, wherein the first contact range andthe second contact range are respectively obtained according to acomparison result between variations of a plurality of detection unitsand a threshold.
 5. The method as claimed in claim 1, wherein the firstcontact range and the second contact range are respectively calculatedaccording to a variation curve of a sum of intensities of each column oreach row of the first detected data and the second detected data.
 6. Themethod as claimed in claim 1, wherein the variation is a differencevalue or a quotient between the second contact range and the firstcontact range.
 7. The method as claimed in claim 1, wherein the firstcontact range and the second contact range are contact widths, contactlengths or contact areas, and the sensing element is a capacitive touchsensor, a resistive touch sensor or an optical touch sensor.